[llvm-commits] Add -arm-long-calls support for ARMFastISel

[Chad Rosier]

Hi Jush,
Overall, LGTM.  When the call is emitted in EmitLibcall is there a difference in the logic when in ARM mode vs. Thumb?

Specifically, this bit of logic:
  // Issue the call.
  MachineInstrBuilder MIB;
  unsigned CallOpc = ARMSelectCallOp(EnableARMLongCalls);
  if (isThumb2) {
    // Explicitly adding the predicate here.
    MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                         TII.get(CallOpc)));
    if (EnableARMLongCalls)
      MIB.addReg(CalleeReg);
    else
      MIB.addExternalSymbol(TLI.getLibcallName(Call));
  } else {
    if (EnableARMLongCalls)
      // Explicitly adding the predicate here.
      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                           TII.get(CallOpc))
            .addReg(CalleeReg));
    else
      // Explicitly adding the predicate here.
      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                           TII.get(CallOpc))
            .addExternalSymbol(TLI.getLibcallName(Call)));
  }

Similarly, in EmitCall can the logic in the else clause be simplified like that in the if (isThumb2) clause?  Specifically, can you make a single call to BuildMI in the else clause for this bit of logic:

  // Issue the call.
  MachineInstrBuilder MIB;
  unsigned CallOpc = ARMSelectCallOp(UseReg);
  if(isThumb2) {
    // Explicitly adding the predicate here.
    MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                 TII.get(CallOpc)));
    if (UseReg)
      MIB.addReg(CalleeReg);
    else if (!IntrMemName)
      MIB.addGlobalAddress(GV, 0, 0);
    else 
      MIB.addExternalSymbol(IntrMemName, 0);
  } else {
    if (UseReg)
      // Explicitly adding the predicate here.
      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                   TII.get(CallOpc))
            .addReg(CalleeReg));
    else if (!IntrMemName)
      // Explicitly adding the predicate here.
      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                   TII.get(CallOpc))
            .addGlobalAddress(GV, 0, 0));
    else
      // Explicitly adding the predicate here.
      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                   TII.get(CallOpc))
            .addExternalSymbol(IntrMemName, 0));
  }


 Chad

On Jun 10, 2012, at 7:59 AM, Jush Lu wrote:

> Hi,
> 
> I removed some unnecessary variables from the patch in last mail,
> please ignore the patch in the last mail, and use the new one attached
> in this mail.
> 
> Thanks,
> Jush
> 
> On Sun, Jun 10, 2012 at 9:30 AM, Jush Lu <jush.msn at gmail.com> wrote:
>> Hi,
>> 
>> This patch adds -arm-long-calls support for ARMFastISel.
>> 
>> It can generate arm long calls for global functions, runtime library
>> calls, and memory intrinsics such as llvm.memset.
>> 
>> The testtcases in the patch show how they work. Basically, these long
>> calls work by blx instructions as the call to non-global callee does
>> in r157336.
>> 
>> Please help me review, thanks.
>> 
>> Thanks,
>> Jush
> <ARMFastISel-arm-long-calls.patch>